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Joint Communication and Positioning Receiver Architecture for DSSS-Overlayed OFDM Waveform
Get PDFpeer reviewedThe integration of satellite systems within the 5G new radio (NR) framework, designated as non-terrestrial networks (NTNs), relies on global navigation satellite systems (GNSS) to achieve precise synchronization. However, dependence on GNSS presents significant vulnerabilities in scenarios involving signal degradation, jamming, or spoofing, alongside increased cost and power consumption issues, particularly in extensive internet of things (IoT) deployments. To address these challenges, this paper proposes an innovative joint communication and positioning (JCAP) receiver architecture, which integrates direct sequence spread spectrum (DSSS) signals into the 5G orthogonal frequency division multiplexing (OFDM) waveform, enabling GNSS-free synchronization and positioning capabilities without embedded pilot overhead. The proposed hybrid architecture jointly exploits DSSS for robust channel parameter estimation and OFDM for high-throughput communication, thereby reducing the pilots signals traditionally required for synchronization and channel estimation. Comprehensive evaluations demonstrate that the proposed JCAP receiver achieves reliable detection and accurate estimation of delay and Doppler parameters, maintaining low bit error rates (BER) under realistic signal-to-interference ratios (SIR). The findings underscore the feasibility and effectiveness of the proposed hybrid scheme, paving the way for resilient GNSS-free operations in 5G NTN environments.9. Industry, innovation and infrastructur
CONTRIBUTIONS TO HYBRID 5G AND GNSS FOR PNT APPLICATIONS
Get PDFGlobal Navigation Satellite Systems (GNSS) have long served as the backbone of positioning services. However, GNSS signals are highly susceptible to interference, spoofing, and blockage, which poses significant challenges for applications that require robust and reliable positioning. Recent advances in fifth-generation (5G) wireless technologies, New Radio (NR), have opened promising pathways to deliver integrated communication and positioning services. Using the existing 5G framework to embed positioning functionalities can potentially mitigate the vulnerabilities inherent in GNSS, facilitating GNSS-independent positioning solutions.
One of the challenges in a position, navigation and timing (PNT) system is the management of the interference from several transmissions; to address the inherent challenge of interference management in dense satellite constellations, this thesis first develops a comprehensive statistical interference model tailored explicitly for non-terrestrial networks (NTN) scenarios involving multiple satellites. Through Monte Carlo simulations, realistic satellite deployments resembling commercial low-earth orbit (LEO) constellations are assessed, resulting in the formulation of a Generalised Extreme Value (GEV) distribution model for interference. This statistical characterisation reveals the interference bounds crucial for an accurate link budget analysis.
Building upon these insights, two novel payload architectures for joint communication and positioning (JCAP) in 5G-NTN are proposed and evaluated: a shared beam architecture, integrating direct-sequence spread spectrum (DSSS) for navigation signals with cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM) for data, and an independent beam architecture, employing separate beams for navigation and communication services. A trade-off analysis between positioning accuracy and spectral efficiency is conducted, quantifying performance analytically via a Pareto frontier. The simulation results demonstrate that precise, metre-level positioning can be maintained consistently while minimising the impact on the loss of data throughput.
The research then introduces an advanced hybrid receiver design explicitly tailored for the integrated DSSS and OFDM signals. Utilising an extended Kalman filter (EKF), the receiver effectively estimates the Doppler shifts, providing resilient observables even in the presence of strong interference. The performance evaluations demonstrate that the proposed receiver structure maintains robust tracking capabilities under challenging signal-to-interference conditions, significantly improving overall system reliability and service continuity.
The comprehensive simulation results validate the viability and practical benefits of integrating the communication and positioning functionalities within 5G-NTN. These findings highlight that existing satellite deployments, supplemented with minimal modifications, can deliver reliable positioning services without relying on external GNSS infrastructures. This approach not only preserves backward compatibility with conventional 5G NTN terminals, but also establishes a solid foundation for the future convergence of communication, positioning, and sensing capabilities envisioned for sixth-generation (6G) wireless networks. Ultimately, this work significantly advances the feasibility of navigation services in NTN deployments without external GNSS support, paving the way for resilient and integrated next-generation wireless services
A Journey With THeSeuSS: Automated Python Tool for Modeling IR and Raman Vibrational Spectra of Molecules and Solids
Get PDFpeer reviewedVibrational spectroscopy is an indispensable analytical tool that provides structural fingerprints for molecules, solids, and interfaces thereof. This study introduces THeSeuSS (THz Spectra Simulations Software)—an automated computational platform that efficiently simulates IR and Raman spectra for both periodic and non-periodic systems. Using DFT, DFTB and machine-learning force field, THeSeuSS offers robust capabilities for detailed vibrational spectra simulations. Our extensive evaluations and benchmarks demonstrate that THeSeuSS accurately reproduces both previously calculated and experimental spectra, enabling precise comparisons and interpretations of vibrational characteristics in various test cases, including H2O and glycine molecules in the gas phase, as well as solid ammonia and solid ibuprofen. Designed with a user-friendly interface and seamless integration with existing computational chemistry tools, THeSeuSS enhances the accessibility and applicability of advanced spectroscopic simulations, supporting research and development in chemical, pharmaceutical, and material sciences
The model of Luxembourg from 1805
No full texteditorial reviewedÜber das Aussehen der Stadt und der Festung am Übergang vom 18. zum 19. Jahrhundert sind wir durch eine faszinierende Quelle außergewöhnlich gut informiert. Es handelt sich um ein großformatiges Stadtmodell (einen sogenannten Plan relief), erstellt von 1802 bis 1805 im Auftrag Napoleons unter der Leitung des Franzosen Martin Boitard.We are exceptionally well informed about the appearance of the town and the fortress at the turn of the 18th and 19th centuries thanks to a fascinating source. This is a large-scale model of the town (a so-called relief map), created between 1802 and 1805 on behalf of Napoleon under the direction of the Frenchman Martin Boitard.Nous disposons d'informations exceptionnellement précises sur l'apparence de la ville et de la forteresse à la fin du XVIIIe et au début du XIXe siècle grâce à une source fascinante. Il s'agit d'une maquette de la ville à grande échelle (appelée « plan relief »), réalisée entre 1802 et 1805 à la demande de Napoléon sous la direction du Français Martin Boitard.U-AGR-8489 - LUXATLAS - UHRMACHER Marti
The Scope of Application of Alternative Dispute Resolution Mechanisms for Financial Consumers: Insights from the EU And Brazil
No full textIn the European Union, the protection of consumers of financial services is often based on the interaction between consumer law and financial legislation and regulation, which depends on the coordination of the personal and material scopes of the two areas. However, this coordination is not always achieved, creating challenges for the fair and equal treatment of consumers dealing with financial institutions. Directive 2013/11/EU on alternative dispute resolution (ADR) illustrates this limitation, as persons who enter into contracts for financial services, but who are not considered “consumers” under the Directive, are excluded from its facilitated out-of-court redress mechanisms. In this context, this study examines whether the personal and material scope of Directive 2013/11/EU is sufficient to provide access to redress for consumers of financial services. Using a legal-theoretical methodology, including doctrinal analysis, case law interpretation and functional comparison, the study interprets the Directive in the light of consumers’ right to access to justice through ADR mechanisms, with a particular focus on the definitions of “consumer,” “trader,” and “contractual obligations,” which determine the scope of the Directive. The functional comparison is first conducted between the EU and its Member States, and then extended to Brazilian law as an international jurisdiction. The Brazilian approach to consumer ADR is based on the protection of consumers by the State as a fundamental constitutional right, complemented by the right of access to justice. Furthermore, this jurisdiction is particularly relevant due to its distinctive online dispute resolution (ODR) framework, geographical representativeness, and status as a developing economy. As an underlying normative intention, the study offers a purposive interpretation of the personal and material scope of the Directive, consistent with the case law of the Court of Justice of the European Union, yet flexible for coherent implementation by Member States. Accordingly, the study constitutes a multi-level, international, and intradisciplinary analysis of Directive 2013/11/EU in relation to consumers’ access to justice in the field of financial services
Hybrid Threats, Chinese ‘Rule by Law’ and Liberal Constitutionalism: On Legal Silence and Exclusion from a Postcolonial Perspective
No full textBack-to-Nature with technologies of the self: A critical mixed methods analysis of aestheticized ideologies on Instagram
No full textpeer reviewedIn this paper, we explore the intersection of natural health, masculinity, and far-right content creators in folkish Instagram to understand how far-right discourses not only euphemize and normalize through lifestyle content but create identities which seem desirable for participants. We do this by closely analyzing usernames and bios on Instagram, extending work which has focused on the visual element to more closely explore the creation of user personae with a both visual and textual elements. This paper draws on both a digital ethnography of 862 Instagram accounts and a critical mixed method analysis of 806 Instagram usernames and biographies. Our analysis of content and digital onomastics shows how terms from nature and health are used to create a positive image of whiteness in three steps: first to euphemize racist content as “white positive”, second it uses natural lifestyle and masculinity to build up “white positive content”. Finally, discourses of whiteness as natural and desirable are taken up in heroic personae by these users and demonstrated in their bios and usernames
Discourse figures in the Luxembourg language debate (2015–2020)
Get PDFpeer reviewedThe societal role of languages in issues of social integration and collective identity has long been a topic of public debate in Luxembourg. In this paper, I examine the latest wave of this language-ideological debate by focusing on the years 2015–2020. The study uses data from different sources and combines different methodological approaches to examine the contributions and perspectives of various social groups of actors to the structure and dynamics of this debate. I introduce the concept of discourse figure, that is, frequent couplings of linguistic forms and ideological motifs tied to different types of actors in discourse, as a unifying analytical lens to the multi-method and multi-sited study of public discourse. The case study is carried out in three steps, first, via a manual analysis of a large media corpus, then, through the computational modeling of a large corpus of user comments from RTL.lu, and last, using a perception study asking participants to make drawings of their experience with multilingualism in Luxembourg. The results show that there is a limited number of discourse figures with structural relevance for the Luxembourg language debate. These figures are found in all datasets and can be classified into three types: language-related, actor-related and feature-related. The ideological core of the central figures in Luxembourg’s public discourse reveals a close connection of the discussion on multilingualism and the role of Luxembourgish with questions of collective identity and social integration. From a methodological perspective, the study demonstrates that a multi-method approach – with the help of the concept of discourse figure – can be used to comprehensively reconstruct the dynamics of the Luxembourg language-ideological debate.10. Reduced inequalitie